I found that achievement gap can be addressed in a number of ways: decreasing class sizes (Carroll, 106), incorporating multiple languages in schools (Gibson, 137), bicultural teachers (Morales, 109. References and links are cited below:

Carroll, K. L., Costner, R. H., Hunt, G. H., Jones, C. R., Ratcliff, N. J., Sheehan, H. C. (2016). Causes of and Solutions to the Achievement Gap: Teachers’ Perceptions. Teacher Educators’ Journal, Volume 9, 97-111. Retrieved from http://www.eric.ed.gov/contentdelivery/servlet/ERICServlet?accno=EJ1095644

Gibson, C. (2016). Bridging English Language Learner Achievement Gaps through Effective Vocabulary Development Strategies. English Language Teaching, Volume 9 (9), 134-138. Retrieved from http://www.eric.ed.gov/contentdelivery/servlet/ERICServlet?accno=EJ1110015

Morales, E. E. (2016). Prospective Teachers from Urban Environments Examine Causes of the Achievement Gap in the United States. International Journal of Higher Education, Volume 5 (2), 101-112. Retrieved from http://www.eric.ed.gov/contentdelivery/servlet/ERICServlet?accno=EJ1099872